Conventional soap bars are the most commonly used agents for cleansing and conditioning the skin. However, it is well known that soap tends to remove natural oils from the skin, thus causing roughness and dryness of the skin which is apparent when the fingers are rubbed across the washed and dried skin. Additionally, the person cleansing with soap often perceives a stinging sensation both when the hands are wet with the aqueous soap and after the hands are rinsed with water to remove the soap composition and dried.
Many modifications of the basic soap composition have been formulated in an attempt to avoid the disadvantages of the soap compositions. One approach has been to add a mildness agent to the soap bar such as 10% to 40% by weight of an alkyl-carboxy substituted sulfonate as shown in U.S. Pat. No. 4,260,570 or 0.25% to 25% by weight of a quaternary ammonium salt as shown in U.S. Pat. No. 4,303,54 or at least 10% by weight of an oil emollient, e.g., a mixture of mineral oil, isopropyl myristate and a polyethyleneoxide ingredient, as shown in U.S. Pat. No. 4,582,626 or up to 40% by weight of a clathrate of urea and free fatty acid as shown in U.S. Pat. No. 3,991,001.
A second approach has been to replace a major proportion of soap with a milder synthetic detergent and to include a superfatting ingredient such as stearic acid. For example, each of U.S. Pat. Nos. 2,894,912, 3,376,229 and 3,879,309 relates to acid pH bars which are milder than soap wherein a mixture of a major proportion of an acyl isethionate salt and a minor proportion of soap is employed as the principal surfactant in place of soap. These compositions also contain from 10% to 40% by weight of a C-6-C-18 carboxylic acid as a superfatting agent and as a binder-plasticizer. U.S. Pat. No. 3,951,842 describes an improved acyl isethionate bar of the type disclosed above which includes a mixture of sodium sulfate, sodium chloride and a linoleic dimer diacid salt as an anti-mushing agent. U.S. Pat. No. 4,007,124 also describes a similar improved acyl isethionate-soap bar which contains from 10% to 20% by weight of a C-12-C-14 alkane sulfonate salt as an anti-mushing agent.
A third approach has been to omit soap as an ingredient, thereby forming a non-soap, synthetic detergent bar having an acid pH. British Patent No. 1,570,142 describes a non-soap acyl isethionate bar containing a mixture of C-12-C-22 straight chain alcohol or acid in combination with a hydrogenated triglyceride as a binder. This binder system provides a plastic, but hard composition which cannot be achieved by either of the binder components alone. Another improvement in the non-soap, acyl isethionate detergent bars is disclosed in U.S. Pat. No. 4,100,097 wherein the described bars further include, by weight, 10% to 30% of paraffin, 5% to 15% of powdered starch and 10% to 30% of dextrin. Similarly, U.K. Application GB No. 2,057,486 discloses an acid pH detergent bar comprising 30% to 80% by weight of an acyl isethionate in combination with 20% to 70% by weight of a binder consisting of a C-12-C-22 fatty acid or fatty alcohol and an alkyl amide. Another modification of the acid pH, non-soap, acyl isethionate bars is described in U.S. Pat. No. 4,046,717 wherein 10% to 20% by weight of a lactate salt and at least 10% by weight of a glutamate salt are employed together with the acyl isethionate detergent to provide a moisturizing detergent bar. An alternative to the non-soap, acid pH, acyl isethionate synthetic detergent bars is disclosed in U.S. Pat. No. 4,335,025 wherein a C-8-C-16 alkyl sulfosuccinate detergent is combined with a C-12-C-22 fatty acid or alcohol and water to yield a mild detergent bar.
A fourth approach has been to cleanse the skin with a liquid cleansing composition containing an emollient and a foaming detergent. One such composition is described in U.S. Pat. No. 3,829,563 which discloses a foaming liquid emulsion containing 10% to 70% by weight of petrolatum emulsified in an aqueous anionic detergent medium. An anhydrous liquid bath oil comprising a dispersion of a particulate organic detergent in a liquid emollient is described in U.S. Pat. No. 4,026,825. A clear, superfatted, liquid, cleansing composition comprising 5% to 25% by weight of a mixture of potassium soap and fatty acids is described in U.S. Pat. No. 4,310,433. An alternative bathing oil composition is described in U.S. Pat. No. 4,529,605 which comprises an emulsion of a liquid emollient, e.g., isopropyl myristate, in an aqueous mixture of nonionic detergent and cationic detergent.
The present compositions differ from the described prior art soap, synthetic detergent-soap and synthetic detergent bars and the foaming cleansing lotions in that they are non-foaming and form a cleansing and conditioning cream in normal use. Furthermore, they differ from the prior art liquid lotions in that they are delivered in bar form, thereby avoiding the emulsion stability problems noted in the prior art liquid compositions. Thus, the described compositions are unique, different and represent a new concept which is not suggested by any of the prior-described compositions.